I guess you could start from L135 anzeigen(tankneu). tankneu is all the information about all liquids already added together and anzeigen is looping through the table and decides the position on the display and on L177-L185 it is giving it to zeigeHier([...stuff...]) label (visible liquid name), name (hidden liquid name, this will be used to check with the color table), menge (amount), maxmenge (max amount), prozent (percent, this is calculated and not in tankneu).
zeigeHier combines the variables into the message for the screen, changes the color and then writes to the screen.
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